Process of fermenting sulfite liquor.



A.-LACK[V!AN.

PROCESS OF FERMENTING SULFITE LIQUOR.

APPLICATION FILED FEB. 26. I912.

1 69,28?o Patented June 11, 1918.

G G Momma;

" meanest,

new and useful Inn i method of treating "hLEEANDER LACKMAN,

application and February as, 19112.

To all whom it may concern.-

Be it known that I, ALaXANnm. LACKMAN, of Germany but now a States, residing at New Yorlc'in the count 1 of New York and State of New York, have invented certain rovements in Processes or Fermenting Sui te Liquor, of which the following; is a specification.

This invention relates to processes of fer menting sulfite liquor; and it comprises a Waste sulfite' liquor to produce alcohol and other valuable products therefrom wherein such Waste sulfite in a heated state With a liquor acidified oi strong acid, best sulininimal amount furic acid, to displace sulfurous acid exist ing as such and as sulfites, is cooled and fermented and is then distilled and concentrated; all as more fully hereinafter set forth and as claimed.

' Waste sulfite liquor is the Watery liquid resulting from the digestion of Wood and the like under pressure with a, solution of a bisuliite, such as bisulfite of lime or a mixture of the bisuliitesoi lime and magnesia,

idolomitic lime, in this country, being often employed in making the original bisulfite solution. About half the Wood remains undissolved as cellulose or paper pulp While the residue (the portion usually called flignone) goes into solution to form vausually) the dissolved ricus complex organic bodies containing sulfur. these bodies are, at least in part, in the nature of sulfonic' acids, united to the bases present (lime or lime and magnesia, organic matters are ordinarily called, for the sake of a name, lignosulfonates. This being a convenient term, it Will be used. As the hot liquor leaves the digester, the

wrelease of pressure causes most of the dissuch, are decomposed solved sulfur dioxid or sulfurous acid, existing as such, to flash into gas; and similarly, the bulk of the bisulfites, existlng as with a liberation of sulfur dioxid- Most of the sulfur dioxid of g tlial form disappears in the original bisulfite solution having gone into organic combination is no longer present as sulfurous acid or sulfites; and most of the residue of that which is present in this releasing operation. Such neutral sulfite of calcium as is formed by expulsion of the sulfur dioxid mostly separates out since it is an insoluble specification of Letters Patent.

PATENT ora ion,

ornntv roan, N. "r.

Zfit0CE$S 0F FERMEINTING SULFITE LIQUOR.

Patented June ill, 1918., Serial No. erases.

Assuming that a typical analysis of the light or unconcentratcd liquor as it comes from the digesters will show it to contain present is not all lignosuli'onate; part of it being of a carbo hydrate nature and fermentable. The cooled liquid can be directly fermented to yield a little alcohol; but this is a diflicult and tedious operation, this being due largely to the antiseptic effect of the sulfites and sulfurous acid present. The amount of these antiseptic bodies is, as just pointed out, not large; but the yeast organism is quite susceptible to their effects. These sulfites cannot'be removed with any sufficient degree of completeness by merely neutralizing the liquid with lime. The neutral calcium sulfite formed is not sufliciently insoluble to prevent its harming the yeast; and, be cause ofthe small amount actually present it is difficult to separate it by filter-pressing or dccantation. The other sulfur combinations present do not seem to affect yeast materially.

In commercial practice, the Waste sulfite liquor is usually evaporated at low temperatures after a careful neutralization to yield a concentrated stable liquid, (Patent 833,634) which may serve an adhesive, as a material for tanning preparations or extracts, for road-making, etc. For most of the purposes to which the concentrated liquor is applied, its contents of the lignosulfonates, or the complexes derived from lignone, is important. And for this reason it is desirable to free it of the carbohydrates which have less value for the stated purposes. By fermenting them, alcohol is produced, and this if recovered may help pay the expense of the operation, while the soluble solids of the residue left after 'l'crmentation contain a concomitantly greater percentage of the more valuable lignosulfonates. lin a tan ning preparation made by concentrating unfrrmented liquor and, of say, 30 Baum density, an analysis made by the usual 'mothods of tannin determination may show, say, pm cont; and overot non-tans while characteristic organic a similar preparation made from the liquidsubmitted to a preliminary f rmentation on analysis may show 18 to 2 per cent. or less. non-tans. This is an important practical difierence. Similarly, the concentrated liquid made from the fermented liquor is better as an adhesive and is better for many tic acid may be used in lieu of sulfuric.

Hydrochloric or oxalic acids may also be used in lieu of sulfuric acid but are more expensive and are not more advanta eous. After this acidifying operation, the iquid can'be fermented in about a quarter the time necessary to bring the untreated liquid to a similar degree of fermentation.

An addition of about 0.02 per cent. sulfuric acid to the liquid of the strength at which it leaves the digester is generally sufiicient though this amount will vary a little one way or the other according to the amount of sulfites present. As a general rule, the addition should be about the amount which is equivalent to the sulfites present. In order to secure a ready and complete expulsion of the sulfur dioxid, the liquid should be hot; and it may advantageously be at a boiling temperature. For the same reason, the liquid is advantageously filmed, sprayed or made into shallow layers; or it may be air-blown. Using these expedients to get rid of the sulfurous acid, some incidental evaporation takes place which is also advantageous.

The hot liquid coming directly from the digestcr may be treated with the acid, being thereafter filmed, sprayed, air blown or otherwise caused to expose a large surface for evaporation and for the removal of the sulfurous acid. Or it may be further heat ed in any suitable way; as by the use of steam coils or steam jets. After expulsion. of the sulfurous acid, the liquid should be cooled and fermented by an addition of yeast; the fermentation being conducted in the ordinary way. It is advantageous but not necessary to use cultures of yeast made from organisms which have been accustomed to sulfite liquor.

In order to secure an economy of heat, the liquid to be treated may be run through a heat-interchanger, taking up heat from outgoing treated. liquor, to a treating vessel luaeaee't where it is treated by adding the desired minimal amount of acid and freed-of sulfurous acid by' filming, spraying or air blasting. The purified liquid may then 'be led away through the heat interchanger (where it gives up heat to incoming liquid) further cooled if necessary and then for mented. After the fermentation, the alcohol may be distilled ofl' and recovered and then the residual liquid concentrated to the desired degree; enerally about 30 Baum this being a stan ard commercial density for liquids of this character. Fermentation is generally complete in a single day.

Any desired type of apparatus may be used for the distillation and concentration; as for example ordinary alcohol stills, such as column stills and charge stills treating the fermented liquid and multiple efi'ects, or other evaporators, treating the dealcoholized. liquid. Multiple efiect evaporators working with low pressure steam in the heating elements of the first efi'ect are desirable.

After the evaporation the concentrated liquid may be treated to convert the calcium lignosulfonate into the corresponding aluminum or chomium salt; as by adding-a concentrated solution of alumina or chromium sulfate and filtering off orotherwise removing the calcium sulfate produced in the reaction. This gives a desirable type of tan-f ning preparations or extracts freed of much inert fermentable matter, and comparatively high in tanning constituents. The sesquioxid bases, alumina and chromium oxids have good tanning properties. The same is true of preparations made with iron sesquioxid; but the iron preparations give a leather with a color which is not liked.

1n the accompanying illustration, I have shown more or less diagrammatically certain apparatus useful in the performance of the described process.

In this showing, 1, l are a air of vats or digesters for treating the siil remove acid. Each is shown provided with a steam coil 2'hung on hangers 3, and with air hlowin device 4 terminating in a minutely per orated pipe 5. llnlet 6 to heat interchanger 7, provided with internal tubes 8, between headers 9 and 10, rovides for the introduction of raw sulfite liquor which passing through the heat interchanger and taking up heat, goes through 11 through either of valved pipes 12 or 13 according to the acid liberating device which may be in use. Treated liquor leaves this acid liberating apparatus through valved pipe 1% and passes through the heat interchanger passing around the internal tubes and givingvup its heat to inflowing liqubr. From the heat I interchanger, the treated liquor may go to any one of a pluralit of fermenting vats 15, 15, 15. As many 0 fite liquor to these ferment ng vats ill) going to the fermentation. tank may he used as the capacity of the plant requires. Valved pipes 16 provide for the introduction of the treated liquor into the ticular vat in which it is required. Air pipe 17 may he used to liquor prior to adding the yeast.

In the use of the foregoing structure one of the vats (1) may be filled with sulfite waste liquor and heated with exhaust or live steam to the desired degree. The heating coils may advantageously be of lead. When the liquor has nearly reached the boiling point compressed air, or steam, advantageously air, is turned on through pipe i. Acid is now added in the small amount necessary to react with the sulfites. Sulfur dioxid will escape with the air and at the same time some evaporation will take place causing I come somewhat more concentrated. When 'the'sulfur dioxid is substantially expelled, the hot liquid is sent through the heat interchanger by 14, and thence to a fermenting vat While fresh liquid from 6, passingup through the interchanger and into the other vat, takes up the heat from the out flowing hot treated liquid. The flow of liquid should he so regulated that the liquid is at about 90 13, this being the host temperature for quick and complete fermentation. Special coolers may he used in addition to the heat interchanger if desired; but the heat inter-- changer with proper operation is sufficient. Fermentation in the fermenting vats is as usual. With the liquor at about 90 F, for mcntation goes on very quickly and may he finished in lest than 2i hours instead of the two or three liquor.

What I claim is 1. The process of treating sulfite liquor which comprises adding sulfuric acid to the hot liquor in substantially the amount equivdays requisite with untreated stir and aerate the Which comprises adding the liquor to bealent to 8G and sulfites present, removing the sulfur diouid in gaseous form and ter menting the acidified liquor.

2. The process of treating sulfite liquor which comprises adding an acid to the hot liquor in substantially the amount equivalent to 30;, and sulfites present removing the sulfur dioirid in gaseous form and fermenting the acidified liquor.

3. The process of treating sulfite Which COIiliilI'lSl-SS adding an acid liquor in substantially the amount equivalent to S0,, end present, removing the sulfur diosiid in gaseous form, fermenting the acidified liquor and removing the alcohol.

l. The proce' liquor to the hot of treating sulfite liquor an acid to the hot liquor in substantially the amount cqui alent to $05 and suliites present, removing the sulfur dioxid in gaseous form fermenting the acidified liquor, removing the alco- 1101 and concentrating the residual. liquid to a thicls: liquor.

5. The process of treating sullite liquor which comprises bringing such liquor to a boil adding an amount of sulfuric acid about equivalent to the sullite oresent, pen mitting suilicient evaporation to ca] 3 off the sulfur dioitid liberated, fermenting" the acidified liquor and removing the alcohol and concentrating to a thick liquid.

6. The process of treating suliite Waste liquor which comprises ringing such liquor to a boil, adding about 0.2 per cent. su acid, cool ing and liei'meutiiig the coolc acidified liquor.

In. testimony whereof, li adii: my signa ture in the presence two suhscrihing Witnesses.

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